1. Field of the Invention
The present invention relates to the field of wire guides having an inflatable balloon adjacent the distal tip, and more particularly to a guide, such as an infusion guide, having a central lumen useful for both fluid communication through the distal tip and also for inflation of the balloon.
2. Description of the Prior Art
A great variety of wire guides have been known in the prior art for addressing particular applications. In many instances, it is desirable that a wire guide be readily advanced and maneuvered through the vascular system and out into the small, distal arteries and vessels with good efficiency. Some applications require the presence of an inflatable balloon adjacent the distal tip of the wire guide, such as in the performing of coronary angioplasties.
Standard coronary balloon angioplasty catheters of the prior art have employed two lumens to separately perform the roles of fluid communication and balloon inflation. In one embodiment, the prior art catheters have comprised a two lumen extruded tube, while other embodiments have used two single lumen extruded tubes extending coaxially. For the two lumen tube, the balloon is assembled to the catheter as a separate assembly. On the coaxial construction, the balloon is formed on the distal end of the outer tube and the annular space between the tubes becomes the inflation channel for the balloon.
Since these prior art catheters have used two separate lumens through the length of the catheter, there have been limitations regarding size. The inflation channel to the balloon needs to be as large as possible to decrease the length of time required to inflate and deflate the balloon. The balloon needs to inflate and deflate quickly because blood flow out into the heart muscle is stopped during the dilating process. The main or central lumen also needs to be as large as possible to allow good pressure measurements, the injection of radiopaque liquids in large enough quantities to produce useful X-ray visualization, and to allow the passage of various sized guide wires. The outside diameter for a coronary balloon catheter is limited to about 4 French (0.054 inches). Consequently, the two lumens used in the prior art catheters need to be fairly small. The inflation lumen of prior art catheters has measured in the range of 0.010 inches to 0.018 inches. The central lumen of prior art catheters has measured in the range of 0.018 inches to 0.021 inches in diameter.
A thrombectomy catheter or gallstone dislodger is described in U.S. Pat. No. 4,561,439 issued to Bishop, et al. on Dec. 31, 1985. The Bishop catheter has a closed, distal end, and includes a spring portion near the distal end. A balloon is attached about the spring portion, and the introduction of fluid into the lumen causes the spring to extend and the balloon to fill.
An elongatable balloon catheter is described in U.S. Pat. No. 4,276,874 issued to Wolvek, et al. on July 7, 1981. The Wolvek catheter includes an extendable, helical coil portion adjacent the distal, closed end. A balloon is secured about the coil portion. A rod extended through the central lumen of the catheter is used to extend the coil portion and thereby stretches the balloon to reduce the outside diameter of the balloon to facilitate movement of the catheter through a passageway.
Several other patents in the prior art have provided a variety of features in association with a balloon catheter. In U.S. Pat. No. 4,467,790 issued to Schiff on Aug. 28, 1984, there is disclosed a percutaneous balloon catheter which includes a balloon at the distal tip. A stylet extends through the balloon and is secured to the distal tip and upon rotation is used to wrap and unwrap the balloon to facilitate the percutaneous insertion of the catheter. A similar balloon catheter having a rotatable support for twisting and untwisting the balloon is shown in U.S. Pat. No. 4,261,339 issued to Hanson, et al. on Apr. 4, 1981.
A steerable guide wire for a balloon dilatation procedure is described in U.S. Pat. No. 4,545,390 issued to Leary on Oct. 8, 1985. The Leary device includes a balloon which is positioned in the region surrounding a coiled wire portion of the guide wire, but the balloon is inflated by means of a separate inflation lumen. In U.S. Pat. No. 4,540,404 issued to Wolvek on Sept. 10, 1985 there is described a balloon catheter which includes a movable sheath which is positioned over the balloon during insertion and then removed from the balloon for inflation.
There has remained a need for a balloon guide which can serve dual purposes in providing a fluid communicating lumen and also an inflatable balloon. The need has also remained for a balloon guide of this type which is a single lumen device that is able to perform two functions through one lumen and which achieves the advantages of a smaller outside diameter with a relatively larger inflation lumen.